The word Ki in Japanese language carries many and nuanced connotations. It can refer to mood, ambience, feeling, a tree, attitude, inclination, atmosphere, caring, worry, attraction, consciousness, the way colour or patterns affect the viewer, or the weather and a range of other possibilities, which can be inferred depending on the context of its use.
Such a way of denoting gives rise to a vast range of nuanced meanings arising from the ancient, and more correct, way of thinking in which all things were seen as connected.
For purposes of Budo practice, Ki has more specific connotations and these, whilst several, lead in to only one. Whilst mood may be relevant, ambience may, or may not, depending on the circumstance. Whilst feeling may, a tree, unless it was to form part of your strategy or to hide behind, may not. Atmosphere should not affect the budoka’s frame of mind. If anything, he should be able to penetrate any atmosphere and inject his ki.
Particularly during training, caring is very relevant. Sharp consciousness is essential, so discard ideas of “no-mind.” Sleep in a safe place if you must wallow in unconscious states, but be fully mindful and be safe in the presence of any weaponry.
Unless you’ve grown up practicing certain shamanic or zogo techniques, there is nothing you can do about the weather, except talk about it. And with the increase of global warming such techniques are ceasing to work as well. When someone attacks, their mood may well have some relevance affecting their intention, but the weather and astrological charts, well, perhaps and perhaps not.
Whatever the ambience, once having made up his mind, an attacker will nevertheless attack. You may get a feeling, that something is not quite right just before the attack. Listen carefully to such feelings and learn to discern. Whether it’s sunny, raining, a storm is up or otherwise, practice to be intensely conscious at all times.
When anyone decides to physically attack, there is one thing coming at you: Intention, closely followed by solid mass. Between the impact and the intention to move, there is a gap.
At first such a gap does not appear to be, just as 16 frames per second gave rise to the appearance of motion. Nowadays, modern film has more than 16 fps and movies appear more real. In nature, the spacing is even more sophisticated.
How does the budoka learn to discern these immense pauses in time and space?
By regular, fully conscious training and no other way. Consciousness of subtleties can only take place through frequent exposure such as in regular training.
Timing and spacing are related to the motion of energy and matter.
Once any attack crosses the perimeter of your maai, if, having intercepted the intention that preceded it, you intercept the forward motion of the attack per se, you can harmonize with it. If not, you will wear it. Full on.
For purposes of Budo, the meaning of Ki is mainly a simple one: Intention.
Aikido is the Way to harmonizing intention, yours and that of others. Yamabiko no michi (this may lead on to other, deeper developments in the trainee, over time).
Having done that, intercepted intention during interaction, everything else follows naturally.
Ki o tsukete kudasai.